Wireless communication devices often require multi-band antennas for transmitting and receiving radio communication signals often called Radio Frequency (RF) signals. For example, network operators providing service on a GSM system in a 900 MHz frequency band typically used in Asia also use a DCS system in a 1800 MHz frequency band typically used in Europe.
Current consumer requirements are for compact wireless communication devices that typically have a miniaturized antenna comprising an antenna radiator structure coupled to a ground plane, the ground plane being typically formed on or in a circuit board of the communications device. The antenna must be able to cover multiple frequency bands to, for instance, accommodate the 850 MHz, 900 MHz, 1800 Mhz and 1900 Mhz bands whilst being compact. Also, there has been a growing need to include a GPS capability on the device, to provide for a GPS capability a GPS antenna or antenna are required in addition to the miniaturized antenna described above. Such GPS antennas should be relatively efficient and stray or parasitic inductances caused by coupling to circuitry (typically also coupled to the miniaturized antenna), such as coupling from flexible connectors (ribbon cable), should be negated or at least reduced. To negate such parasitic inductances capacitors can be used, however conventional capacitors may need to be relatively large therefore requiring valuable space within the communications device.
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